Synchronized thread rolling tool



Nov. 21, 1967 5.0. BEDKER SYNCHRONIZED THREAD ROLLING TOOL Filed Nov.10, 1964 INVENTOR' o 'BRU BEDKER FIG.4

A T TORNEVS United States Patent Ofiice 3,353,390 Patented Nov. 21, 19673,353,390 SYNCHRONIZED THREAD ROLLING TOOL Bruce D. Bedker, MountClemens, Mich, assignor to Leo W. Bedker, Detroit, Mich. Filed Nov. 10,1964, Ser. No. 410,205

' 3 Claims. (Cl. 72104) The present invention relates to a synchronizedthread rolling tool or attachment of the type illustrated and describedin US. Letters Patent 2,701,484 of Feb. 8, 1955, to Leo W. Bedker. Theinvention of that patent addresses itself to an improvement in threadrolling and related rolling apparatus, in accordance with which a pairof forming rolls, upon initially engaging a rotating workpiece indirections transverse of the axis of the latter, are permitted to have aslight degree of relative differential movement, or relative angularphase shift, about the respective roll axes, being positivelygear-connected to thereafter rotate together in exact angular phaserelation under a drive from the workpiece. Thus, the initialdifferential of movement permits the threading or other forming rolls tobring their working formations into exactly timed synchronism, so as totrack properly with threading or the like progressively formed by themas the rolls are advanced toward the workpiece axis.

In the patent referred to above, the desired result was attained byproviding for a slight lost motion in the driving connection between agear and one of the forming rolls, also in providinga mount for theholder head for the rolls which permits one roll to engage the workpieceslightly before engagement of the latter by the other roll. Inaccordance with the present invention, the same principle of allowingfor a corrective lost motion is followed. That is, provision is madethat one of the forming rolls will be the first of the two to engage therotating workpiece and be driven thereby; yet the second roll will bedriven positively, prior to engaging the workpiece and after lost motionhas been practically instantaneously taken up in gearing interconnectingthe rolls, until it, too, contacts the workpiece. After this, theworkpiece takes over the drive of the forming rolls, without regard tothe gearing. In addition, means are also provided to effect amicro-adjustment in the angular relationship of the rolls to insure thatthey will be in exactly phased relation when rolling commences. Suchmeans may also introduce a change in depth of intermesh at the teeth ofcertain gear members which drivingly interconnect the forming rolls, butfull driving capacity is retained until the roll set has contacted theworkpiece, after which the latter drives the rolls in a true trackingrelationship.

While reference is herein made to thread rolling equipment, it will beevident to those skilled in the art that the tool or attachment of thepresent invention is, like that of the Bedker patent, equally wellsuited to knurling, to the formation of splines by rolling, etc., in allof which a slight error in relative angularity or phase relation of apair of rolls upon engaging a workpiece may, unless compensated orcorrected, result in damage to the gearing and, at best, the productionof inacceptable work.

It is a general object of the invention to provide an improved rollingtool or attachment of the sort described, characterized by a pair offorming rolls rotatable on a bifurcated mounting head on parallel,laterally spaced axes and having meshing gear means for the positiverotational drive thereof, as driven by a rotating workpiece in which thedesired phase adjustment of the rolls is made possible by providing foran adjusting bodily shift of a pinion of a meshing spur gear train whichdrivingly interconnects the rolls. The adjustment permits a variation inthe distance of the pinion axis from the axes of gears meshed by thepinion, i.e., a shift of the pinion in a direction approximately normalto a theoretical line through the gear axes. Thus, considering one ofthe gears to be a driver rotated by the workpiece and driving the otherthrough the adjustable pinion, the machinist may make a very fine,micrometgr-like corrective adjustment of the position of the latter,such as will bring the gears, and the forming rolls gear-connectedthereto, into an exactly phased relationship necessary for propertracking of the rolls in fully engaging and rolling the piece.

It is seen that should the rolls be out of exactly proper angularcoordination at the instant of attack on the workpiece, for example, tothe extent of a fraction of the width of a pinion or gear tooth,consequently of an intended rolled workpiece formation, such as mightresult in the marring of or rolling of double the intended threadformations on the workpiece, the possible fractional error is correctedby the adjustable pinion provisions of the invention.

It is a further object of the invention to provide a rolling tooloperating on the general principle of adjusting the pinion axis-to-gearaxis distance described above, in which the micro-adjustment to providethe desired phase correction, one set up, is thereafter rigidly andprecisely maintained throughout the production run, without furtherchange.

More specifically, the invention provides a rotatable eccentric (onwhich the interconnecting drive pinion is journaled) for shifting thelatter bodily relative to the remainder of the gear train drivinglyinterconnecting the thread forming rolls, plus frictional anchor meansfor thereafter locking the eccentric and pinion against bodily departurefrom the desired setting. In this matter of locking the setting, theinvention provides an annular locking flange on a manually rotatableeccentric-carrying member, which flange is concentric with the axis ofrotative adjustment of the member and is adapted to be strongly heldfrictionally against an outer wall face of the attachment to lock theadjusted setting.

In further accordance with the invention, the provisions for effectingthe desired adjustment are all readily and conveniently accessible fromthe exterior of the tool or attachment, without the need for removingthe latter from an operating mount, for example, the tool slide of anautomatic screw machine. Furthermore, the arrangements of the improvedtool are such as to make it very easily assembled and dismantled.

The foregoing as well as other objects will become more apparent as thisdescription proceeds, especially when considered in connection with theaccompanying drawings illustrating the invention, wherein:

FIG. 1 is a perspective view illustrating the improved threading orrolling tool of the invention;

FIG. 2 is a fragmentary view in horizontal section on the plane 2-2 ofFIG. 1;

FIG. 3 is a view in vertical section along line 3-3 of FIG. 2, showing aworkpiece in successive positions of engagement with the forming rollsof the attachment or tool, including a solid line position upon initialcontact engagement with a workpiece, and the dotted line position uponsubstantial completion of the rolling operation;

FIG. 4 is a fragmentary view similar to FIG. 3, illustrating variousadjusted positions of the inter-connecting pinion of the tool (solid anddotted lines); and

FIG. 5 is a fragmentary view in vertical section along line 55 of FIG.2.

As indicated above, the invention deals with the general type of rollingtool in which, if the forming rolls were positively geared together forcoordinated drive without rolling of a workpiece would be impossible,and gear tooth breakage might take place if the rolls weresimultaneously engaged.

As hereinafter further described, and as described in detail in theBedker patent identified above, the difliculty arises because of thefact that, as the tool is advanced toward the rotating workpiece, itstwo forming rolls, in initially contacting the piece are subjected to africtional effort, even if the latter is rotatively stationary, tendingto rotate the rolls in opposite directions. On the other hand, thedynamic frictional effect of the rotating workpiece upon the rolls is ina common angular direction of rotation of the latter.

Consequently, in the case of one thread roll the effect of the twoforces, i.e., essentially static frictional and rotatively driving, isadditive, while in the case of the other thread roll it is subtractive;and it is this differential which requires compensation or correction bythe relative differential rotation of the two rolls in coming intoengagement with the rotating workpiece, to permit the rolling formationsof the rolls to come into the exact desired angular relationship forproper tracking with the workpiece. The matter will be further dealtwith in connection with FIG. 3 of the drawings.

The improved tool is generally designated by the reference numeral 10.It comprises a block-like head 12 of bifurcated shape, which head is ingeneral constituted by upright front and rear housing members 13, 14,respectively, between which the forming rolls 16, 17 are received, beingjournaled on parallel horizontal shafts or axles 18, 19, respectively,by the head members 13 and 14. Suitable provisions are made to adjustthe lateral spacing of the rolls 16, 17 relative to one another. Forexample, the shaft 19 may be mounted in eccentric bushing devices 20 fora relatively coarse lateral adjustment, and the shaft 18 may besustained in elongated slots 21 for a relatively fine, final adjustment,and held therein by a set screw 22, in the manner illustrated anddescribed in the patent to Leo W. Bedker 3,110,202 of Nov. 12, 1963. Theinvention does not concern these provisions.

As shown in FIG. 3, the thread or like forming rolls 16, 17 are adaptedto be driven, respectively, by relatively small diameter gears 24, 25 infixed angular, coaxial relation thereto, which gears mesh downwardlywith larger diameter gears 26, 27, respectively, journaled on rods orshafts 28 which are borne in horizontal spaced, parallel relation to oneanother by tool head 12; and the gears 26, 27 are drivinglyinterconnected by a small diameter pinion 29 in adjustable meshtherewith in accordance with the invention.

As shown in FIG. 1, the gear shafts 28 are held in place by screw means31 taking into their ends from the exterior of the front head member 13;and the head 12 is also provided with a bottom dovetail formation 33 formating reception in a similar shaped formation on a tool slide (notshown), by means of which the tool or attachment is adapted to beadvanced toward and retracted away from a rotating workpiece W (FIG. 3).Typically, this slide will be a slide of a conventional type ofautomatic screw machine.

The tool head 12 is also equipped with other provisions not germane tothe present invention, for example, adjusting screw means at 34 by whichthe axial position of the attachment on the tool slide may be adjustedand maintained, further screw means 35, and the like.

Before detailing the structural improvements of the invention, it may bepointed out that, reference being had to FIG. 3 of the drawings, even ifthe workpiece W were rotatably fixed, an upward movement of the tool 10into initial contact with the piece would cause frictional forces to beexerted on the rolls 16, 17 tending to rotate the roll 17 clockwise inthe direction of the dotted line arrow (left-hand side of roll 17 inFIG, 3) and the roll 16 in the opposite, counterclockwise direction(dotted line arrow to the left of roll 16); and this effect exists alsoin the case of roll 16 when the workpiece W is rotating and driving therolls, for example, in the direction of the arrow applied to theworkpiece in FIG. 3.

On the other hand, as the rolls 16, 17 continue to be dynamicallyengaged and driven by the rotating Workpiece in moving from the solidline relationship with the latter in FIG. 3 to the dotted center linerelationship at or possibly beyond a horizontal plane through the rollaxes, the effect on rolls 16, 17 is to rotate the latter in the sameangular direction, i.e., counterclockwise, per the solid line arrowsapplied to the rolls. Thus, the resultant eifect, in the case of theroll 17 is the difference between the two forces, while the resultanteffect on the roll 16 is the addition of the two forces; and it followsthat, unless compensated, the rolls 16, 17 will have differentialrotation in advancing in rolling engagement with the workpiece, withdestructive effect on the gearing, or, in any event, a substantialfailure of the rolling formations on the rolls to track the workpieceproperly as rolling proceeds. Bedker Patent 2,701,484 shows means tomake the necessary compensation, but further means may be required tofurther correct the roll phasing for truly precise tracking.

To the end of making such correction very accurately, the tool 10provides for the use of an improved adjustable mount for theintermeshing pinion 29 which is generally designated by the referencenumeral 37. This device comprises a rotatable adjusting member 38 havinga cylindrical, eccentric-carrying barrel 39 which is mounted to rotateon a horizontal axis in a journal opening 40 formed through the fronthead member 13 of the tool, a very close tolerance being observed.Outwardly of the upright wall face of member 13, the barrel 39 isprovided with an integral annular locking flange 42, which substantiallyoverlies the outer face of the member surrounding the opening 40; andstill further outwardly, the barrel 29 of device 37 is provided with aknurled fingerpiece 43.

The barrel 39 is provided with an axial bore 45 extending through thecenter thereof and well beyond its rear; and this bore receives alocking screw or stem 46, the end of which is formed at 47 for threadingengagement in a tapped bore 48 of the rear member 14 of the tool head12. The unthreaded body portion of stem 46 is received in an outercounterbore 48' of bore 48, and an axial clearance of the stem at 46permits axial movement thereof in the counterbore 48' when the stem isthreadedly taken up. This has the effect of clamping the flange 42 offingerpiece 43 against the face of house member 13, and thus lockingbarrel 39 in an adjusted position.

The journaling barrel portion is provided with an operating eccentric 50of cylindrical shape to the rear of its own cylinder formation; and thedrive transmitting pinion 29 is journaled on eccentric 50 for operatingrotation about an axis eccentric of journal barrel 39. Split ring means,generally designated by the reference numeral 52, surround the screw orstem 46 directly to the rear of pinion 29, holding the latter in fixedaxial relation to the stem as the pinion and barrel assembly movesaxially upon threaded taking up or loosening of the stem.

As shown in FIG. 5, the barrel member 39 is provided, directly behindits locking flange 42, with a radially extending stop pin 54 receivablein an arcuate slot 55 opening outwardly through the forward face of headmember 13 and radially inwardly of the barrel members journal opening orbore 40. Thus, with the screw or stem 46 loosened somewhat, thefingerpiece 43 may be manipulated to a limited extent in either angulardirection, correspondingly shifting the eccentric 50, and the pinion 29journaled thereon, about the axis of stem 46. The latter can then beretightened to lock the pinion axis in the adjusted position, the lockflange 42 taking firm frictional engagement with the outer face of headmember 13 for this purpose. If desired, screw or stem 46 may be furtherbacked off to bring the flange to the dotted line position of FIG. 2,whereupon the pin 54 may be axially cleared from arcuate slot 55,enabling a greater degree of angular adjustment. However, it is the morelimited adjustment of the eccentric and pinion 29 with which theinvention is primarily concerned.

The outer face of head member :13 is appropriately calibrated at 57(FIGS. 1 and for coaction with an indicator marking 58 of lock flange42.

FIG. 3 shows a typical adjustment of the eccentric 50 to bring thepinion 29 into a less-than-full or perfect meshing engagement with theintermediate gear 26, which is the consequence of a shift of the axis ofthe eccentric (hence of the pinion) in a direction approximately normalto a theoretical line through the axes of gears 26 and 27. FIG. 4 of thedrawings shows, in solid line, an other position with the pinion 29closer to said theoretical line of the gear axes and a consequent fulland complete meshing engagement of the teeth of pinion 29 with those ofboth of the intermediate gears 26, 27. This is the In setting (FIGS. 1and 5). It is seen from FIG. 4 that a full permissible rotation ofbarrel 39, upon loosening of the screw of stem 46, will have the effectof shifting the eccentric and pinion, on the path of the doubleheadedarrow A in FIG. 4, away from the fully engaged relationship of the toothmembers to the Out setting. Micrometer-like intermediate settings areavailable.

In any position of adjustment in this range of shift, it will beappreciated that, considering the roll 16 as a driver rotated byworkpiece W and acting through gears 24, 26 and pinion 29 to drivegear-s 27, 25 and roll 17, the rolls may be phase-adjusted in a veryfine manner, i.e., to an extent representing a small fraction of thewidth of a tooth (and of a rolled formation) or representing a wholewidth or more. Hence in this manner the invention may also serve thefunction of the structure shown in the Bedker patent first identifiedabove.

Despite some change in depth of tooth intermesh occasioned by the bodilypinion shift, the pinion and gear teeth remain amply engaged for apositive transmission of rotative thrust through the gearing between therolls 16, 17, once the slight lost motion upon the formers engaging theworkpiece has been absorbed, to rotate the latter in precise synchronismup until the time that the workpiece assumes the drive.

It is seen in FIGS. 1 and 2 that the pinion adjusting device 37 is fullyaccessible from the exterior of the tool and it is not necessary toremove the latter from the tool slide to make the desired adjustment.Upon making the same, retightening of stem 46 clamps the eccentric 20tightly in adjustable position, and maintains that adjustment throughthe entirety of production. In general, the manipulations involved inthe use of the tool 10 are positive in nature, requiring no attentionafter the making of an original setting for the production run.

Broadly considered, the invention alfords means to provide for theprecise adjustment of phasing of the rotation of the forming rolls uponengagement with the work, by means of a micrometer or coarser adjustmentof a component of spur type gear means which drivingly interconnects therolls, and thereafter maintaining the adjustment.

What I claim as my invention is:

1. In a rolling tool of the type having a pair of forming rollsengageable with a rotating workpiece in a plane paralleling a planesubstantially including the axes of said rolls, pairs of meshing gearsdrivingly connected to the respective rolls, and pinion having meshingengagement with and drivingly connecting a gear of each pair withanother, the improvement to adjust the distance from the axis of saidpinion to the axes of at least one pair of said gears for a preciselyphased drive of the rolls, comprising means mounting said pinion formovement transverse of a theoretical line through the gear axes, saidtool having a head by which said rolls, gears and pinion are supportedfor rotation, said mounting means comprising an eccentric memberjournaled for adjusting rotation on said head on an axis paralleling thegear axes, said pinion being journaled by said eccentric member forrotation on an axis laterally spaced from and paralleling said eccentricmember axis.

2. In a rolling tool of the type having a pair of forming rollsengageable with a rotating workpiece in a plane paralleling a planesubstantially including the axes of said rolls, pairs of meshing gearsdrivingly connected to the respective rolls, and a pinion having meshingengagement with and drivingly connecting a gear of each pair with oneanother, the improvement to adjust the distance from the axis of saidpinion to the axes of at least one pair of said gears for a preciselyphased drive of the rolls, comprising means mounting said pinion formovement transverse of a theoretical line through the gear axes, andmeans to lock said mounting means against movement from an adjustedposition, said tool having a head by Which said rolls, gears and pinionare supported for rotation, said mounting means comprising an eccentricmember journaled for adjusting rotation on said head on an axisparalleling the gear axes, said pinion being journaled by said eccentricmember for rotation on an axis laterally spaced from said parallelingsaid eccentric member axis.

3. In a rolling tool of the type having a pair of forming rollsengageable with a rotating workpiece in a plane paralleling a planesubstantially including the axes of said rolls, pairs of meshing gearsdrivingly connected to the respective rolls, and a pinion having meshingengagement with and drivingly connecting a gear of each pair with oneanother, the improvement to adjust the distance from the axis of saidpinion to the axes of at least one pair of said gears for a preciselyphased drive of the rolls, comprising means mounting said pinion formovement transverse of a theoretical line through the gear axes, andmeans to lock said mounting means against movement from an adjustedposition, said tool having a head by which said rolls, gears and pinionare supported for rotation, said mounting means comprising an eccentricmember journaled for adjusting rotation on said head on an axisparalleling the gear axes, said pinion being journaled by said eccentricmember for rotation on an axis laterally spaced from and parallelingsaid eccentric member axis, said locking means including a part in fixedrelation to said eccentric member, and :means to fixedly engage saidpart against a portion of said head in an adjusted position of theeccentric member.

References Cited UNITED STATES PATENTS 1,359,572 11/1920 Brennan 721043,110,202 11/1963 Bedker 72104 FRANCIS S. HUSAR, Primary Examiner.

1. IN A ROLLING TOOL OF THE TYPE HAVING A PAIR OF FORMING ROLLS ENGAGEABLE WITH A ROTATING WORKPIECE IN A PLANE PARALLELING A PLANE SUBSTANTIALLY INCLUDING THE AXES OF SAID ROLLS, PAIRS OF MESHING GEARS DRIVINGLY CONNECTED TO THE RESPECTIVE ROLLS, AND PINION HAVING MESHING ENGAGEMENT WITH SAID DRIVINGLY CONNECTED A GEAR OF EACH PAIR WITH ANOTHER, THE IMPROVEMENT TO ADJUST THE DISTANCE FROM THE AXIS OF SAID PINION TO THE AXIS OF AT LEAST ONE PAIR OF SAID GEARS FOR A PRECISELY PHASED DRIVE TO THE ROLLS, TRANSPRISING MEANS MOUNTING SAID PINION FOR MOVEMENT TRANSVERSE TO A THEORETICAL LINE THROUGH THE GEAR AXES, SAID TOOL HAVING A HEAD BY WHICH SAID ROLLS, GEARS AND PINON ARE SUPPORTED FOR ROTATION, SAID MOUNTING MEANS COMPRISING AN ECCENTRIC MEMBER JOURNALED FOR ADJUSTING ROTATION ON SAID HEAD ON AN AXIS PARALLELING THE GEAR AXES, SAID PINION BEING JOURNALED BY SAID ECCENTRIC MEMBER FOR ROTATION ON AN AXIS LATERALLY SPACED FROM AND PARALLELING SAID ECCENTRIC MEMBER AXIS. 